ISTANBUL, TURKEY – Iran has charged three Americans with espionage, after they strayed during a hiking trip in northern Iraq this past July, in a move likely to complicate US overtures toward Iran.

“The three are charged with espionage. Investigations continue into the three detained Americans in Iran,” Tehran prosecutor Abbas Jafari Dolatabadi said on Monday. Family members have made appeals for their release, shown snapshots of the three visiting tourist sites in the Middle East, and say they wandered into Iran by accident.

“We believe strongly that there is no evidence to support any charge whatsoever,” Clinton said. “And we would renew our request on behalf of these three young people and their families that the Iranian government exercise compassion and release them, so they can return home.”

According to Iranian law, the charges could result in the death penalty. But past precedent suggests that the decision by Iran’s hard-line judiciary could be a bid by some right-wing factions in Iran to block any chance of US-Iran reconciliation. It could also be used as a diplomatic card to gain concessions, or to exacerbate already tricky nuclear negotiations between Iran and the West.

Weeks of bloody street clashes after a disputed presidential election had prompted ultraconservative leaders, security chiefs, and prosecutors to accuse the US, Britain and Israel of fomenting the unrest and trying to overthrow the government in a “velvet revolution.”

The prosecutor said on Monday, according to the official IRNA news agency, that an “opinion [on their case] will be given in the not distant future.”

The Kurdish area of northern Iran is especially sensitive, due to a slow-burn conflict with anti-Iranian PJAK guerrillas based in Iraq, which frequently target Iranian police and security forces. Iran and many outside analysts charge that those Kurdish fighters – who work alongside Turkish PKK guerrillas – have received American support in their fight against Iran. Washington denies the claim.

The espionage charge comes just days after Iran’s supreme religious leader Ayatollah Sayyed Ali Khamenei marked the 30th anniversary of the takeover of the US Embassy in Tehran by military students with a tough anti-US speech.

“The American government is a really arrogant power and the Iranian nation will not be deceived with its apparent reconciliatory behavior,” Ayatollah Khamenei said.

Roxana Saberi, also charged with espionage, was later freedIran is also holding academic Kian Tajbakhsh, a dual US-Iran citizen, who was arrested shortly after the violence began and charged along with 140 senior reformist figures and activists with national security offenses aimed at toppling the regime. He was sentenced to 12 years in jail last month for activity related to the post-election protests.

Earlier this year dual US-Iranian citizen Roxana Saberi was arrested in Tehran, charged with espionage, and sentenced to eight years in prison. The sentence was reversed on appeal, and she was released to her parents in May, after more than three months in prison.

Analysts at the time said her arrest was a deliberate attempt by hard-line faction “spoilers” to derail President Barack Obama’s attempts at dialogue with Tehran.

The arrest of the hikers “could also facilitate things,” suggested one close observer in Tehran on Monday. “If Ahmadinejad intervenes with a presidential decree, as he did with [Saberi], at least he can pose as somebody who is in favor of softening tensions.”